Tunnel gage

ABSTRACT

In one embodiment, a device for measuring a length of a bone tunnel is provided. The device includes: a gauge comprising an annular shaft coupled to a handle, the handle including a constrained channel configured for receiving a passing pin from the annular shaft and displaying the passing pin in relation to a scale. In another embodiment, a method for measuring length of the bone tunnel is provided. A method and another device are provided.

BACKGROUND

1. Field

The invention disclosed herein relates to a device for use in ligamentreconstruction surgery, and more specifically, a device and method forperforming measurements.

2. Description of the Related Art

Common techniques for reconstruction of ligaments require the drillingof a tunnel through bone. For example, reconstruction of a torn anteriorcruciate ligament (ACL) requires drilling through the femur of apatient. Once a femoral tunnel has been drilled. a surgeon needs toperform measurements to determine the depth of the tunnel to aide inselection of the appropriate repair technique.

While a variety of devices are available to measure the length of thefemoral tunnel, many of these devices are complicated to use and maylead to confusion during surgical procedures. For example, some devicesmake use of a guide wire that is passed into the femoral tunnel andreceived by a measuring device as it exits the femoral tunnel.Unfortunately, the various receiving devices presently available oftendo not securely retain the guide wire. Accordingly, this may lead toerroneous measurements, and worse yet to glove damage or laceration ofthe surgeon.

Thus, what are needed are methods and apparatus to provide for accurateand safe measurement of the femoral tunnel. Preferably, the methods andapparatus are simple and easy to understand during a surgical procedureas well as cost-effective.

SUMMARY

In one embodiment, a device for measuring a length of a bone tunnel isprovided. The device includes: a gauge comprising an annular shaftcoupled to a handle, the handle including a constrained channelconfigured for receiving a passing pin from the annular shaft anddisplaying the passing pin in relation to a scale.

In another embodiment, a method for measuring length of the bone tunnelis provided. The method includes: placing a gauge over a passing pin,the tunnel gauge including an annular shaft coupled to a handle, thehandle also having a constrained channel configured for receiving thepassing pin from the annular shaft and displaying the passing pin inrelation to a scale; and, comparing a reference mark on the passing pinto the gauge to determine the length.

In a further embodiment, a device for measuring a length of a bonetunnel is provided. The device includes: a passing pin having a regionconfigured to be maintained within a constrained channel of ameasurement device; and, a gauge including an annular shaft coupled to ahandle, the handle also having a constrained channel configured forreceiving the passing pin from the annular shaft and displaying thepassing pin in relation to a scale.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the invention are apparent from thefollowing description taken in conjunction with the accompanyingdrawings in which:

FIG. 1 is an isometric view of a tunnel gauge according to an embodimentof the invention;

FIG. 2 is an isometric view of a handle of the tunnel gauge of FIG. 1,from a different angle;

FIGS. 3A, 3B and 3C, collectively referred to herein as FIG. 3, provideanother isometric view of the handle of the tunnel gauge of FIG. 1. FIG.3A provides the isometric view of a complete embodiment of the handle,while FIG. 3B provides a cutaway of the isometric view of FIG. 3A. FIG.3C provides a close-up view of the cutaway shown in FIG. 3B,additionally with a cross-section of the passing pin;

FIG. 4 provides an isometric view of a passing pin suited for use withthe tunnel gauge of FIG. 1;

FIG. 5 is a blown up isometric view of a portion of the handle of thetunnel gauge with the passing pin loaded therein; and,

FIG. 6 is an isometric cutaway view of the tunnel gauge in use with thepassing pin.

DETAILED DESCRIPTION

Disclosed herein are methods and apparatus for performing measurementsof a bone tunnel. As discussed herein, the bone tunnel is a femoraltunnel (i.e., a hole that has been drilled through a portion of a femurof a patient). However, this is merely exemplary and it is not limitingof the teachings herein.

Generally, the apparatus disclosed herein is a two-part apparatus. Inorder to measure the femoral tunnel, a first part, a passing pin, isinserted into the femoral tunnel. Insertion of the passing pin isstopped when a reference mark on the passing pin aligns with an outersurface of the femoral condyle. A second part of the device, a tunnelgauge, is then disposed over a portion of the passing pin that hasemerged from an opposing side of the femur. By placing the tunnel gaugeagainst the opposing side of the femoral condyle and by referencing ascale on the tunnel gauge, a surgeon is able to determine a depth of thefemoral tunnel.

Referring now to FIG. 1, there is shown an exemplary tunnel gauge 10according to the teachings herein. In this example, the tunnel gauge 10includes a shaft 1 and a handle 2. Generally, the shaft 1 is mounted tothe handle 2 at a base 3.

Note that merely for convenience of referencing and an explanation ofthe teachings herein, the terms “distal” and “proximal” as well as othersuch relational or descriptive terms are used. This terminology shouldnot be construed to imply any orientation for implementation of themethods and apparatus disclosed herein. Generally, the term “distal” and“proximal” are with respect to an individual using the device (e.g., aphysician). For example, when inserting a passing pin, an end of thepassing pin that is being inserted may be referred to as a “distal” endof the passing pin. Similarly, when placing the tunnel gauge 10 againstthe femur, it may be considered that the shaft 1 is a distal portion ofthe tunnel gauge 10, while the handle 2 is a proximal portion of thetunnel gauge 10.

In the exemplary embodiment, the tunnel gauge 10 is disposed about alongitudinal axis, A. Again, the longitudinal axis, A, and any othertechniques for referencing are merely for purposes of explanation andare not limiting of the teachings herein.

In the embodiment shown, the shaft 1 is an annular cylinder. The shaft 1includes a receiver 4, a tapered section 5, and an elongated section 6.The shaft 1 may be mounted to the handle 2 at the body 3 by any one (ormore) of a variety of suitable techniques. For example, the shaft 1 maybe threaded into a receiving section within the body 3. The shaft 1 maybe glued, hot melted, fastened or otherwise mated or joined with thebody 3.

Generally, the shaft 1 has an inner diameter designed to accommodate apassing pin (as shown in FIG. 4, and as discussed further herein). Forexample, the shaft 1 may have an inner diameter that is slightly largerthan 2.4 mm or 2.7 mm, such that it may securely accommodate passage ofthe 2.4 mm or 2.7 mm passing pin, respectively.

In the embodiment shown, the shaft 1 is an annular cylinder. The shaft 1includes a receiver 4, a tapered section 5, and an elongated section 6.The shaft 1 may be mounted to the handle 2 at the base 3 by any one (ormore) of a variety of suitable techniques. For example, the shaft 1 maybe threaded into a receiving section within the base 3. The shaft 1 maybe glued, hot melted, fastened or otherwise mated or joined with thebase 3.

The handle 2 includes a central channel 9. The channel 9 is configuredto receive the passing pin as it emerges from the elongated section 6 ofthe shaft 1. In order to view the central channel 9 (and therefore thepassing pin), a window 7 is provided within the body of the handle 2. Inthis example, the window 7 presents as a cutaway along a length of thehandle 2.

Disposed within the window 7 is at least one gauge 8. The gauge 8 isdisposed along a length of the channel 9 within the window 7.Accordingly, as the passing pin is received within the channel 9, andextends into the handle 2, a depth of the femoral tunnel may beascertained. That is, the gauge 8 includes at least one scale formeasuring depth of the femoral tunnel (i.e., a length of the femoraltunnel). This will be explained in greater detail further herein.

In this example, the gauge 8 is provided in centimeters, withsubdivisions of millimeters. However, any linear scale deemedappropriate may be used in the gauge 8 (i.e., system international (SI),English, metric or other standards may be used).

Referring now to FIG. 2 some of the foregoing aspects are shown fromanother angle. In addition, it may be seen that the handle 2 may includean exit-way 12 from the channel 9. Generally, the exit-way 12 may beprovided to facilitate cleaning of the handle 2 after use. For example,it may be desirable to flush a sterilizing cleaning fluid through atleast one of the receiver 4 and the exit-way 12 to ensure removal of alldebris as well as sterilization of the tunnel gauge 10.

Referring to FIGS. 3A and 3B, additional isometric views of the handle 2are shown. FIG. 3A is provided merely for understanding the depiction inFIG. 3B, which depicts a cutaway portion of the handle 2. As shown inFIG. 3B, the channel 9 may be configured with a “C” shapedcross-section. That is, the channel 9 may be configured to securelyretain the passing pin while providing for display thereof. An exampleof this is better shown in FIG. 3C.

Referring now to FIG. 3C there is shown an exploded view of the cutawayportion of the channel 9 of FIG. 3B. Further, in this illustration, aportion of a passing pin 21 is shown. As may be seen in FIG. 3C, thechannel 9 may include at least one section of retaining material 31.More specifically, retaining material 31 may be included to retain thepassing pin 21 within the channel 9. In this example, retaining material31 is disposed symmetrically about the channel 9. However, in someembodiments, retaining material 31 is provided on merely one side of thechannel 9. In use, the retaining material 31 provides for observation ofthe passing pin 21 while narrowing an open portion of the channel 9substantially enough that the passing pin 21 could not be diverted outof the channel 9 (i.e., the open portion of the channel 9 has a widththat is less than a diameter or width of the passing pin 21).

In this embodiment, the retaining material 31 provides for a“constrained channel” 9. It may be considered that the term “constrainedchannel” generally refers to any type of channel that may becharacterized as having a particular geometry (e.g., a cross-section)that provides for retention of the passing pin 21 or any other similarcomponent (e.g., a guide wire, a drill, a drill shank, and the like).

More specifically, in this example, the passing pin 21 exhibits across-section of a dimension, denoted as “CS.” The constrained channel 9has a relatively narrow opening. That is, a dimension for the openingprovided for display of the passing pin 21 is less than that of thecross-section of the passing pin 21. Accordingly, it should beunderstood that the constrained channel 9 may have a narrow opening thegenerally limits the capability of the passing pin to migrate from thechannel 9.

Also shown in FIG. 3C, is a measuring mark 33. In this example, themeasuring mark 33 is characterized as a single line disposed about acircumference (or perimeter, as the case may be) of the passing pin 21.In some embodiments, the measuring mark 33 is disposed about the passingpin 21 by use of laser etching. However, any technique for providing ameasuring mark 33 that is deemed appropriate may be used.

In some embodiments (not shown), the measuring mark 33 includes aplurality of marks. For example, the measuring mark 33 may includeanother scale. The another scale may be compared to markings in thegauge 8.

Referring now to FIG. 4, an embodiment of the passing pin 21 is shown.In this example the passing pin 21 is a unitary device. The passing pinmay be flexible, rigid or exhibit any appropriate combination ofproperties. The passing pin 21 may include a reference mark 23 whichserves as a stop point during insertion of the passing pin 21 into thefemoral tunnel. In addition, the passing pin 21 may include at least onemarking indicator 24 to enhance visibility of the reference mark 23. Inthis example, the marking indicator 24 is an elongated stripe thatextends along a portion of the length of the passing pin 21.

In some embodiments, the passing pin 21 includes a fluted end. Thefluted end may be provided so that the passing pin 21 may also providefor drilling of the femoral tunnel. In this example, the passing pin 21includes a pointed end which facilitates its insertion into the femoraltunnel, once the femoral tunnel has been drilled and the drill removed.The pointed end of the passing pin 21 allows it to penetrate anydrilling debris remaining in the tunnel. In use, the passing pin 21 isinserted into the femoral tunnel until the reference mark 23 is alignedwith a distal cortex of the femur.

Referring back to FIG. 1, once the passing pin 21 has been inserted, thetunnel gauge 10 is disposed over the portion of the passing pin 21 whichextends from the femur, and in some instances from a skin of thepatient. Once the shaft 1 of the tunnel gauge 10 has been disposed overthe passing pin 21, the shaft 1 is then pushed through the surroundingtissue. Accordingly, the tapered section 5 of the shaft 1 facilitatesinsertion of the shaft 1 by displacing the tissue. Once the receiver 4has been abutted against a proximal cortex of the femur, it is possibleto accurately measure a depth of the femoral tunnel.

Referring now to FIG. 5, an embodiment of the tunnel gauge 10 with thepassing pin 21 loaded therein is shown. It may be seen that, in thisexample, the femoral tunnel is about 41 mm deep.

According to FIG. 6 a cutaway view of the tunnel gauge 10 and passingpin 21 is shown in use. All surrounding tissue has been removed fromthis illustration to better depict cooperation of the passing pin 21with the tunnel gauge 10.

Having thus introduced embodiments of the tunnel gauge 10, someadditional aspects are now provided.

In some embodiments, the handle 2 and the shaft 1 are a unitarystructure. For example, the handle 2 and the shaft 1 may be fabricatedfrom a biocompatible plastic. This may be performed by injection moldingor other suitable techniques. In some additional embodiments, one of thehandle 2 and the shaft 1 is fabricated from a plastic or polymericmaterial while the other component is fabricated from metal or ametallic material. One exemplary polymeric material is polyphenylsulfone(PPSU). PPSU may be characterized as a material having a high heatresistance and excellent hydrolytic stability. Other materials that maywithstand repeated cycling through sterilization environment (i.e.,cleaning with steam, alcohol or other suitable materials) and thatprovide desired structural integrity may be used.

The passing pin 21 may be provided in a variety of configurations. Forexample, the passing pin 21 may be generally cylindrical (such as in theform of a wire), may be annular (such as in the form of a straw), or ofanother cross-sectional geometry (such as a square, a rectangle, atriangle, or an n-gon) as deemed appropriate and suited for use with theconstrained channel 9. The passing pin 21 may include at least one loopor eyelet, such as for carrying suture. Although discussed herein as thepassing pin 21, any device suited for insertion through the femoraltunnel (or any other bone tunnel) may be used with the tunnel gauge 10.For example, the tunnel gauge 10 may be configured to receive a drill.

In some embodiments, the handle 2 may be separated from the shaft 1 tofacilitate cleaning and sterilization of the tunnel gauge 10.

Although presented herein with regards to reconstruction of ligamentsand drilling of a femoral tunnel, the tunnel gauge 10 may be used toascertain a depth or length of any type of bone tunnel, as deemedappropriate.

While the invention has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention.Therefore, it is intended that the invention not be limited to theparticular embodiment disclosed as the best mode contemplated forcarrying out this invention, but that the invention will include allembodiments falling within the scope of the appended claims.

What is claimed is:
 1. A gauge for measuring a length of a bone tunnel,the gauge comprising: an annular shaft having an inner diameter andcoupled to a handle, the handle comprising: a proximal end, a tapereddistal end, and a substantially flat, elongate body extending from theproximal end to the distal end; a constrained channel within the handlebody extending from the proximal end to the distal end, the constrainedchannel in direct communication with the inner diameter of the annularshaft and configured for receiving a passing pin from the inner diameterof the annular shaft, the constrained channel including at least onesection of retaining material to retain the passing pin within theconstrained channel; and a window defined by a cutaway along a length ofthe handle body to expose a visible length of the constrained channel,the window enabling a display of the passing pin in relation to a scale;wherein opposing sides of the handle body comprise bilateral depressionsextending from a top surface to a bottom surface of the handle bodyconfigured for grip on the handle; and wherein the distal end of thehandle comprises a base configured for separating from the annularshaft.
 2. The gauge as in claim 1, wherein the constrained channelcomprises a C-shaped cross-section.
 3. The gauge as in claim 1, whereinan open portion of the constrained channel has a width which is lessthan a cross-sectional dimension of the passing pin.
 4. The gauge as inclaim 3, wherein the open portion of the constrained channel is anexit-way configured to facilitate cleaning.
 5. The gauge as in claim 1,wherein the annular shaft comprises at least one of a tapered sectionand an elongated section.
 6. The gauge as in claim 1, wherein theretaining material is disposed symmetrically about the constrainedchannel.
 7. The gauge as in claim 1, wherein the window comprises thescale disposed along the visible length of the constrained channel. 8.The gauge as in claim 1, wherein the retaining material is disposed onone side of the constrained channel.
 9. The gauge as in claim 1, whereinthe inner diameter of the annular shaft is selected to be slightlylarger than a cross-sectional dimension of the passing pin.
 10. Thegauge as in claim 9, wherein the inner diameter of the annular shaft isslightly larger than 2.4 mm or slightly larger than 2.7 mm.
 11. A devicefor measuring a length of a bone tunnel, the device comprising: a gauge,the gauge comprising: an annular shaft having an inner diameter andcoupled to a handle, the handle comprising: a proximal end, a tapereddistal end, a substantially flat, elongate body extending from theproximal end to the distal end, and a constrained channel extending fromthe proximal end to the distal end, the constrained channel in directcommunication with the inner diameter of the annular shaft andconfigured for receiving a passing pin from the inner diameter of theannular shaft, the constrained channel including at least one section ofrestraining material to retain the passing pin within the constrainedchannel; and a window to expose a visible length of the constrainedchannel, the window enabling a display of the passing pin in relation toa scale, wherein opposing sides of the handle comprise bilateraldepressions extending from a top surface to a bottom surface of thehandle; wherein the distal end of the handle comprises a base configuredfor separating from the annular shaft; and a passing pin that exhibits across-sectional area configured to be maintained within the constrainedchannel of the handle of the gauge, the passing pin comprising a flutedend for drilling into bone.
 12. The device as in claim 11, wherein thepassing pin comprises a generally circular cross-section.
 13. The deviceas in claim 11, wherein the gauge is fabricated from at least one of abiocompatible material, a metallic material and a polymeric material.14. The device as in claim 11, wherein the gauge is fabricated frompolyphenylsulfone.
 15. The device as in claim 11, wherein the retainingmaterial is disposed symmetrically about the constrained channel. 16.The device as in claim 11, wherein the retaining material is disposed onone side of the constrained channel.